This invention relates to a sensor for use in a sensor system for in-situ monitoring of lubricant oil quality and to a method of manufacturing the sensor. In this regard, this sensor is particularly adapted for use in the system of copending application referred to above.
As discussed in said copending application, lubricant oil in use in automotive applications or other combustion engine applications is subjected to an aging process as a result of its use in the engine operation. The exposure of oil to high temperature zones in the presence of NO.sub.x, moisture and air are main factors contributing to chemical changes which decrease the oils lubricating effectiveness.
As a result of the this decrease in its effectiveness, detrimental effects may result on the engine parts, for example, accelerated corrosion.
In addition to the break up of the lubricant, corrosivity also increases as the oil ages because degradation products of various type accumulate. Accumulation of other contaminants will also occur simultaneously, including mineral acids such as sulfur, nitrogen and hydrohalic based acids, soot and water. The final result is an oil whose acidity, corrosivity and viscosity has substantially increased as it reaches the end of its useful life, which as previously indicated, can result in disastrous consequences when continued in use in an internal combustion engine.
Up until the filing of the above-referenced copending application, there had been no system or method of measuring the deterioration of oil in-situ in an automotive environment. The current practices of determining oil condition require laboratory measurement such as titration of total base numbers, i.e. TBN, which is defined as the number of miligrams of KOH required to neutralize all acidic constituents present in one gram of the sample of oil.
In accordance with the invention, a sensor element is provided particularly adapted for use in a system for example, in accordance with that described in copending application Ser. No. 067,983, which takes advantage of the corrosive effects of spent oil as a means of providing an electrically functioning indicator sensor. Thus in accordance with the invention, the problem of having to conduct oil testing in a laboratory environment is avoided.